/*
 *   This program is free software: you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation, either version 3 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

/*
 *    CSVSaver.java
 *    Copyright (C) 2004-2012 University of Waikato, Hamilton, New Zealand
 *
 */

package weka.core.converters;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.Collections;
import java.util.Enumeration;
import java.util.Vector;

import weka.core.AbstractInstance;
import weka.core.Capabilities;
import weka.core.Capabilities.Capability;
import weka.core.DenseInstance;
import weka.core.Instance;
import weka.core.Instances;
import weka.core.Option;
import weka.core.SparseInstance;
import weka.core.Utils;

/**
 * <!-- globalinfo-start --> Writes to a destination that is in CSV
 * (comma-separated values) format. The column separator can be chosen (default
 * is ',') as well as the value representing missing values (default is '?').
 * <p/>
 * <!-- globalinfo-end -->
 * 
 * <!-- options-start --> Valid options are:
 * <p/>
 * 
 * <pre>
 * -F &lt;separator&gt;
 *  The field separator to be used.
 *  '\t' can be used as well.
 *  (default: ',')
 * </pre>
 * 
 * <pre>
 * -M &lt;str&gt;
 *  The string representing a missing value.
 *  (default: ?)
 * </pre>
 * 
 * <pre>
 * -N
 *  Don't write a header row.
 * </pre>
 * 
 * <pre>
 * -decimal &lt;num&gt;
 *  The maximum number of digits to print after the decimal
 *  place for numeric values (default: 6)
 * </pre>
 * 
 * <pre>
 * -i &lt;the input file&gt;
 *  The input file
 * </pre>
 * 
 * <pre>
 * -o &lt;the output file&gt;
 *  The output file
 * </pre>
 * 
 * <!-- options-end -->
 * 
 * @author Stefan Mutter (mutter@cs.waikato.ac.nz)
 * @version $Revision$
 * @see Saver
 */
public class CSVSaver extends AbstractFileSaver implements BatchConverter, IncrementalConverter, FileSourcedConverter {

    /** for serialization. */
    static final long serialVersionUID = 476636654410701807L;

    /** the field separator. */
    protected String m_FieldSeparator = ",";

    /** The placeholder for missing values. */
    protected String m_MissingValue = "?";

    /** Max number of decimal places for numeric values */
    protected int m_MaxDecimalPlaces = AbstractInstance.s_numericAfterDecimalPoint;

    /** Set to true to not write the header row */
    protected boolean m_noHeaderRow = false;

    /**
     * Constructor.
     */
    public CSVSaver() {
        resetOptions();
    }

    /**
     * Returns a string describing this Saver.
     * 
     * @return a description of the Saver suitable for displaying in the
     *         explorer/experimenter gui
     */
    public String globalInfo() {
        return "Writes to a destination that is in CSV (comma-separated values) format. " + "The column separator can be chosen (default is ',') as well as the value " + "representing missing values (default is '?').";
    }

    /**
     * Returns an enumeration describing the available options.
     * 
     * @return an enumeration of all the available options.
     */
    @Override
    public Enumeration<Option> listOptions() {
        Vector<Option> result = new Vector<Option>();

        result.addElement(new Option("\tThe field separator to be used.\n" + "\t'\\t' can be used as well.\n" + "\t(default: ',')", "F", 1, "-F <separator>"));

        result.addElement(new Option("\tThe string representing a missing value.\n" + "\t(default: ?)", "M", 1, "-M <str>"));

        result.addElement(new Option("\tDon't write a header row.", "N", 0, "-N"));

        result.addElement(new Option("\tThe maximum number of digits to print after the decimal\n" + "\tplace for numeric values (default: 6)", "decimal", 1, "-decimal <num>"));

        result.addAll(Collections.list(super.listOptions()));

        return result.elements();
    }

    /**
     * <!-- options-start --> Valid options are:
     * <p/>
     * 
     * <pre>
     * -F &lt;separator&gt;
     *  The field separator to be used.
     *  '\t' can be used as well.
     *  (default: ',')
     * </pre>
     * 
     * <pre>
     * -M &lt;str&gt;
     *  The string representing a missing value.
     *  (default: ?)
     * </pre>
     * 
     * <pre>
     * -N
     *  Don't write a header row.
     * </pre>
     * 
     * <pre>
     * -decimal &lt;num&gt;
     *  The maximum number of digits to print after the decimal
     *  place for numeric values (default: 6)
     * </pre>
     * 
     * <pre>
     * -i &lt;the input file&gt;
     *  The input file
     * </pre>
     * 
     * <pre>
     * -o &lt;the output file&gt;
     *  The output file
     * </pre>
     * 
     * <!-- options-end -->
     * 
     * @param options the list of options as an array of strings
     * @throws Exception if an option is not supported
     */
    @Override
    public void setOptions(String[] options) throws Exception {
        String tmpStr;

        tmpStr = Utils.getOption('F', options);
        if (tmpStr.length() != 0) {
            setFieldSeparator(tmpStr);
        } else {
            setFieldSeparator(",");
        }

        tmpStr = Utils.getOption('M', options);
        if (tmpStr.length() != 0) {
            setMissingValue(tmpStr);
        } else {
            setMissingValue("?");
        }

        setNoHeaderRow(Utils.getFlag('N', options));

        tmpStr = Utils.getOption("decimal", options);
        if (tmpStr.length() > 0) {
            setMaxDecimalPlaces(Integer.parseInt(tmpStr));
        }

        super.setOptions(options);

        Utils.checkForRemainingOptions(options);
    }

    /**
     * Gets the current settings of the Classifier.
     * 
     * @return an array of strings suitable for passing to setOptions
     */
    @Override
    public String[] getOptions() {
        Vector<String> result = new Vector<String>();

        result.add("-F");
        result.add(getFieldSeparator());

        result.add("-M");
        result.add(getMissingValue());

        if (getNoHeaderRow()) {
            result.add("-N");
        }

        result.add("-decimal");
        result.add("" + getMaxDecimalPlaces());

        Collections.addAll(result, super.getOptions());

        return result.toArray(new String[result.size()]);
    }

    /**
     * Returns the tip text for this property.
     * 
     * @return tip text for this property suitable for displaying in the
     *         explorer/experimenter gui
     */
    public String noHeaderRowTipText() {
        return "If true then the header row is not written";
    }

    /**
     * Set whether to not write the header row
     * 
     * @param b true if no header row is to be written
     */
    public void setNoHeaderRow(boolean b) {
        m_noHeaderRow = b;
    }

    /**
     * Get whether to not write the header row
     * 
     * @return true if no header row is to be written
     */
    public boolean getNoHeaderRow() {
        return m_noHeaderRow;
    }

    /**
     * Set the maximum number of decimal places to print
     * 
     * @param maxDecimal the maximum number of decimal places to print
     */
    public void setMaxDecimalPlaces(int maxDecimal) {
        m_MaxDecimalPlaces = maxDecimal;
    }

    /**
     * Get the maximum number of decimal places to print
     * 
     * @return the maximum number of decimal places to print
     */
    public int getMaxDecimalPlaces() {
        return m_MaxDecimalPlaces;
    }

    /**
     * Returns the tip text for this property.
     * 
     * @return tip text for this property suitable for displaying in the
     *         explorer/experimenter gui
     */
    public String maxDecimalPlacesTipText() {
        return "The maximum number of digits to print after the decimal " + "point for numeric values";
    }

    /**
     * Sets the character used as column separator.
     * 
     * @param value the character to use
     */
    public void setFieldSeparator(String value) {
        m_FieldSeparator = Utils.unbackQuoteChars(value);
        /*
         * if (m_FieldSeparator.length() != 1) { m_FieldSeparator = ","; System.err
         * .println(
         * "Field separator can only be a single character (exception being '\t'), " +
         * "defaulting back to '" + m_FieldSeparator + "'!"); }
         */
    }

    /**
     * Returns the character used as column separator.
     * 
     * @return the character to use
     */
    public String getFieldSeparator() {
        return Utils.backQuoteChars(m_FieldSeparator);
    }

    /**
     * Returns the tip text for this property.
     * 
     * @return tip text for this property suitable for displaying in the
     *         explorer/experimenter gui
     */
    public String fieldSeparatorTipText() {
        return "The character to use as separator for the columns/fields (use '\\t' for TAB).";
    }

    /**
     * Sets the placeholder for missing values.
     * 
     * @param value the placeholder
     */
    public void setMissingValue(String value) {
        m_MissingValue = value;
    }

    /**
     * Returns the current placeholder for missing values.
     * 
     * @return the placeholder
     */
    public String getMissingValue() {
        return m_MissingValue;
    }

    /**
     * Returns the tip text for this property.
     * 
     * @return tip text for this property suitable for displaying in the
     *         explorer/experimenter gui
     */
    public String missingValueTipText() {
        return "The placeholder for missing values, default is '?'.";
    }

    /**
     * Returns a description of the file type.
     * 
     * @return a short file description
     */
    @Override
    public String getFileDescription() {
        return "CSV file: comma separated files";
    }

    /**
     * Resets the Saver.
     */
    @Override
    public void resetOptions() {
        super.resetOptions();

        setFileExtension(".csv");
    }

    /**
     * Returns the Capabilities of this saver.
     * 
     * @return the capabilities of this object
     * @see Capabilities
     */
    @Override
    public Capabilities getCapabilities() {
        Capabilities result = super.getCapabilities();

        // attributes
        result.enable(Capability.NOMINAL_ATTRIBUTES);
        result.enable(Capability.NUMERIC_ATTRIBUTES);
        result.enable(Capability.DATE_ATTRIBUTES);
        result.enable(Capability.STRING_ATTRIBUTES);
        result.enable(Capability.MISSING_VALUES);

        // class
        result.enable(Capability.NOMINAL_CLASS);
        result.enable(Capability.NUMERIC_CLASS);
        result.enable(Capability.DATE_CLASS);
        result.enable(Capability.STRING_CLASS);
        result.enable(Capability.MISSING_CLASS_VALUES);
        result.enable(Capability.NO_CLASS);

        return result;
    }

    /**
     * Saves an instances incrementally. Structure has to be set by using the
     * setStructure() method or setInstances() method.
     * 
     * @param inst the instance to save
     * @throws IOException throws IOEXception if an instance cannot be saved
     *                     incrementally.
     */
    @Override
    public void writeIncremental(Instance inst) throws IOException {

        int writeMode = getWriteMode();
        Instances structure = getInstances();
        PrintWriter outW = null;

        if (getRetrieval() == BATCH || getRetrieval() == NONE) {
            throw new IOException("Batch and incremental saving cannot be mixed.");
        }
        if (getWriter() != null) {
            outW = new PrintWriter(getWriter());
        }

        if (writeMode == WAIT) {
            if (structure == null) {
                setWriteMode(CANCEL);
                if (inst != null) {
                    System.err.println("Structure(Header Information) has to be set in advance");
                }
            } else {
                setWriteMode(STRUCTURE_READY);
            }
            writeMode = getWriteMode();
        }
        if (writeMode == CANCEL) {
            if (outW != null) {
                outW.close();
            }
            cancel();
        }
        if (writeMode == STRUCTURE_READY) {
            setWriteMode(WRITE);
            // write header
            if (!getNoHeaderRow()) {
                if (retrieveFile() == null && outW == null) {
                    // print out attribute names as first row
                    for (int i = 0; i < structure.numAttributes(); i++) {
                        System.out.print(structure.attribute(i).name());
                        if (i < structure.numAttributes() - 1) {
                            System.out.print(m_FieldSeparator);
                        } else {
                            System.out.println();
                        }
                    }
                } else {
                    for (int i = 0; i < structure.numAttributes(); i++) {
                        outW.print(structure.attribute(i).name());
                        if (i < structure.numAttributes() - 1) {
                            outW.print(m_FieldSeparator);
                        } else {
                            outW.println();
                        }
                    }
                    outW.flush();
                }
            }
            writeMode = getWriteMode();
        }
        if (writeMode == WRITE) {
            if (structure == null) {
                throw new IOException("No instances information available.");
            }
            if (inst != null) {
                // write instance
                if (retrieveFile() == null && outW == null) {
                    System.out.println(inst);
                } else {
                    outW.println(instanceToString(inst));
                    // flushes every 100 instances
                    m_incrementalCounter++;
                    if (m_incrementalCounter > 100) {
                        m_incrementalCounter = 0;
                        outW.flush();
                    }
                }
            } else {
                // close
                if (outW != null) {
                    outW.flush();
                    outW.close();
                }
                m_incrementalCounter = 0;
                resetStructure();
                outW = null;
                resetWriter();
            }
        }
    }

    /**
     * Writes a Batch of instances.
     * 
     * @throws IOException throws IOException if saving in batch mode is not
     *                     possible
     */
    @Override
    public void writeBatch() throws IOException {

        if (getInstances() == null) {
            throw new IOException("No instances to save");
        }
        if (getRetrieval() == INCREMENTAL) {
            throw new IOException("Batch and incremental saving cannot be mixed.");
        }
        setRetrieval(BATCH);
        setWriteMode(WRITE);
        if (retrieveFile() == null && getWriter() == null) {

            if (!getNoHeaderRow()) {
                // print out attribute names as first row
                for (int i = 0; i < getInstances().numAttributes(); i++) {
                    System.out.print(getInstances().attribute(i).name());
                    if (i < getInstances().numAttributes() - 1) {
                        System.out.print(m_FieldSeparator);
                    } else {
                        System.out.println();
                    }
                }
            }
            for (int i = 0; i < getInstances().numInstances(); i++) {
                System.out.println(instanceToString(getInstances().instance(i)));
            }
            setWriteMode(WAIT);
            return;
        }
        PrintWriter outW = new PrintWriter(getWriter());
        if (!getNoHeaderRow()) {
            // print out attribute names as first row
            for (int i = 0; i < getInstances().numAttributes(); i++) {
                outW.print(Utils.quote(getInstances().attribute(i).name()));
                if (i < getInstances().numAttributes() - 1) {
                    outW.print(m_FieldSeparator);
                } else {
                    outW.println();
                }
            }
        }
        for (int i = 0; i < getInstances().numInstances(); i++) {
            outW.println(instanceToString((getInstances().instance(i))));
        }
        outW.flush();
        outW.close();
        setWriteMode(WAIT);
        outW = null;
        resetWriter();
        setWriteMode(CANCEL);
    }

    /**
     * turns an instance into a string. takes care of sparse instances as well.
     * 
     * @param inst the instance to turn into a string
     * @return the generated string
     */
    protected String instanceToString(Instance inst) {
        StringBuffer result;
        Instance outInst;
        int i;
        String field;

        result = new StringBuffer();

        if (inst instanceof SparseInstance) {
            outInst = new DenseInstance(inst.weight(), inst.toDoubleArray());
            outInst.setDataset(inst.dataset());
        } else {
            outInst = inst;
        }

        for (i = 0; i < outInst.numAttributes(); i++) {
            if (i > 0) {
                result.append(m_FieldSeparator);
            }

            if (outInst.isMissing(i)) {
                field = m_MissingValue;
            } else {
                field = outInst.toString(i, m_MaxDecimalPlaces);
            }

            // make sure that custom field separators, like ";" get quoted correctly
            // as well (but only for single character field separators)
            if (m_FieldSeparator.length() == 1 && (field.indexOf(m_FieldSeparator) > -1) && !field.startsWith("'") && !field.endsWith("'")) {
                field = "'" + field + "'";
            }

            result.append(field);
        }

        return result.toString();
    }

    /**
     * Main method.
     * 
     * @param args should contain the options of a Saver.
     */
    public static void main(String[] args) {
        runFileSaver(new CSVSaver(), args);
    }
}
